A set of scale-model tests was carried out at the wave basin of the Leibniz University Hannover to extend the range of wave steepness values analysed in run-up, overtopping and armour layer stability studies, focusing on oblique extreme wave conditions and on their effects on a gentler slope breakwater’s trunk armour and roundhead. The paper describes the model set-up and operation concentrating on the measurement techniques used in those tests, namely on the innovative techniques for armour layer damage characterization. @en

No âmbito do projeto HYDRALAB+ (H2020-INFRAIA-2014-2015), foi realizado no LNEC um conjunto de ensaios em modelo físico bidimensional (2D) de um perfil de um quebra-mar de talude em enrocamento, construído à escala geométrica 1:30, para diferentes condições de agitação marítima e níveis de maré correspondentes a cenários de alterações climáticas. Estas experiências tinham como objetivo analisar o dano, o espraiamento e o galgamento, nesses cenários. Em paralelo, na FEUP, e em colaboração com Deltares, foram realizados testes com a mesma configuração de quebra-mar, mas utilizando um modelo físico tridimensional (3D), construído à escala geométrica 1:35. Os resultados obtidos permitiram analisar a evolução do dano no manto resistente do quebra-mar (talude de barlamar, talude de sotamar e cabeça), assim como o galgamento, para condições com e sem sobrelevação do nível médio do mar, considerando ou não a reconstrução do talude do quebra-mar entre testes consecutivos da mesma série de testes. Foram também realizados testes com ondas multidirecionais. O presente trabalho incide sobre a análise da evolução do dano para as diferentes sequências de tempestade em cenários de alterações climáticas. O dano é avaliado com base no tradicional método de contagem de blocos removidos e ainda com base no parâmetro adimensional do dano, S recorrendo a técnicas estereofotogramétricas. É também feita uma avaliação do parâmetro E2D. Em termos gerais, concluiu-se que não havia diferenças significativas entre os testes com danos cumulativos e com a reconstrução do quebra-mar após cada teste. Observou-se, também, que o dano era mais elevado na proximidade da superfície livre e que aumentava com a altura de onda significativa. Os danos foram, em geral, menores nos testes com ondas multidirecionais.@en

This paper studies novel ways to evaluate armour damage in physical models of coastal structures. High-resolution damage data for reference rubble mound breakwaters obtained under the HYDRALAB+ joint-research project are analysed and discussed. These tests are used to analyse the way to describe damage, the influence of the sequence of testing, and touches on the possible influence of sea level rise. Results of two test programmes were used. Firstly, 3D physical model tests carried out at the University of Porto, in cooperation with Deltares, were used. Here a wide breakwater trunk was used for statistical reasons. Additionally, 2D test results from LNEC were analysed. Tests for a sea level rise scenario resulted in less damage to the seaside slope. In addition, clear differences between “cumulative damage” and “rebuild” test series were noticed. However, significant scatter was also observed in the result of tests carried out under identical conditions. It was also concluded that the damage to the trunk was lower in the tests with short-crested waves. The design values for the damage depth E2D proposed by Hofland et al. (2011) were partly in line with the experimental results presented. Since the relation between S and the depth of damage E does not hold true for non-standard cases, it seems better to use a parameter based on the local damage depth when testing such a structure. The reliability of a damage number for a test on the stability of a trunk can be improved by either increasing the relative size (width) of the test section or repeating the test.@en

This paper describes the experiments performed at the National Laboratory for Civil Engineering (LNEC) aiming at simulating, in a flume, the wave propagation along a constant slope bottom that ends on a sea wall coastal defence structure, a common structure employed in the Portuguese coast. The objective of these tests is to calibrate the parameters of FUNWAVE, a Boussincsq type model, for wave propagation in coastal regions. This is the first step in the validation of a methodology to combine numerical and physical models in the study of the interactions between beaches and structures. This work is performed in the framework of the Composite Modelling of the Interactions between Beaches and Structures (CoMIBBs) project, a joint research activity of the HYDRALAB III European project.@en